There is an eye-opening technical development in household digital video devices, and an increase in the resolution of video is one example of this development. However, it can be said that connections among devices such as camcorders that capture video images using cameras, devices that record and reproduce television programs (DVD (Digital Versatile Disc) recorders, BD (Blue-Ray Disc) recorders, and the like), game devices, and television receivers are less than perfect.
MPEG-2 (Moving Picture Experts Group phase 2) is used, for example, at the time of compressing an HDTV (HighDefinition Television) interlaced moving image in BS (Broadcasting Satellite) digital broadcasting. MPEG-2 is also used in all DVD software. Video streams compressed using MPEG-2 is recorded in DVD software.
In addition, AVC (Advanced Video Coding) which has a compression ratio twice as high as that of MPEG-2 has been started to be employed in camcorders in recent years for its compression efficiency. Regarding BD recorders as well, products that have AVC encoders installed therein and feature long-time recording as a sales point have become available on the market. In contrast, HDMI (High Definition Multimedia Interface) has been becoming an industry standard as an interface that connects digital devices. For example, Patent Document 1 describes the details of the HDMI standard.
HDMI is an interface for digital household devices. HDMI is arranged for AV (Audio Visual) household devices by adding an audio transmission function, a copyright protection function (unauthorized copy preventing function for digital content or the like), and a chrominance transmission function to DVI (DigitalVisual Interface) which is a connection standard between a PC (Personal Computer) and a display. The HDMI 1.0 specification has been established in December of 2002.
HDMI transmits non-compressed digital audio and video and has an advantage that there is no image quality/sound quality deterioration. HDMI is currently standardized on the full-specification high-definition television (full HD: resolution is horizontal 1920 pixels×vertical 1080 lines) function. Since video and audio can be transferred without compression from a player to a television side, a dedicated chip or software such as a decoder is not required. Also, an intelligent function is provided, with which connected devices can recognize each other.
Also, since video/audio/control signals are sent through a single cable, there is an advantage that the wiring between AV devices can be simplified. Since a control signal and the like can be sent, AV devices can easily operate in conjunction with one another.
Patent Document 1: WO2002/078336